Non-Maleficence is one of the Four Pillars of Medical Ethics alongside Autonomy, Justice and Beneficence - and a vital concept that every aspiring doctor must understand.

Whether you’re preparing for your MMI interviews, tackling ethical scenarios, or aligning your thinking with NHS core values, mastering non-maleficence will set you apart from other applicants.

This guide is filled with practical interview tips, real-life case studies, and model answers - designed to help you approach non-maleficence like a future healthcare professional.

On your journey to UK medical school, understanding the principle of “do no harm” isn’t just helpful - it’s absolutely essential.

non malificence medical ethics four pillars medicine interview

What Is Non-Maleficence? Key Facts for UK Medical Interviews

Before you start to prepare answers or analyse complex ethical scenarios about Non-Maleficence, it is essential to have a firm grasp of what this Pillar really means - and why it is so vital to understand in both medical school interviews and your future career.

Here is a quick summary of what you should know about the Pillar of Non-Maleficence:

Non-Maleficence means “do no harm” - it is an ethical duty to avoid causing physical, emotional, or psychological harm to patients.
It’s one of the Four Pillars of Medical Ethics, alongside the Pillar of Beneficence, Autonomy, and Justice – all of which you are expected to understand and apply in interviews.
It guides doctors to act responsibly and with caution, especially when treatments carry risks or unintended consequences.
The principle applies to both action and inaction. Sometimes doing less, or nothing at all, is the safest and most ethical choice for a patient.
Common ethical dilemmas, such as refusing treatment, over-treatment, and end-of-life decisions, often centre around this pillar.

Definition of Non-Maleficence (Four Pillars of Medical Ethics Explained)

Definition: ‘Non-Maleficence’’ means ‘do no harm’. It is the obligation to avoid causing harm to patients - through actions, mistakes or poor decision-making.

Etymology: From the Latin ‘malficentia’ (meaning ‘evil-doing’). It is the direct ethical opposite of ‘beneficence’ or doing what is in the best interests of the patient.

Key Points to Understand Non-Maleficence:

Non-maleficence is proactive, not passive. Doctors must take steps to prevent harm and minimise risks to patient safety.
Non-Maleficence is a concept that applies to both actions and omissions (for example, failing to diagnose a health condition can be equally as harmful as making a treatment error.
Patient safety is a cornerstone of this principle, including avoiding unnecessary treatments, investigations or interventions.

What does non-maleficence mean in simple terms?

Non-maleficence simply means “do no harm.” In practical terms, it means that doctors must avoid causing unnecessary physical, emotional, or psychological harm to patients. It also means stopping or avoiding treatments that may cause more harm than good.

How do doctors use non-maleficence in real life?

Doctors use non-maleficence every day when balancing risks and benefits before offering any treatment. This includes avoiding unnecessary tests, preventing medical errors, choosing safer alternatives where possible, and stopping interventions that may harm vulnerable patients. The principle guides clinicians to prioritise patient safety above all else.

👉🏻 Read more: Ultimate Medicine Interview Preparation Guide

Non-Maleficence vs Beneficence: Key Differences for Interview Scenarios

Beneficence:

Focus: Doing good and acting in the best interests of the patient

Example: Starting chemotherapy for a patient with breast cancer

Non-Maleficence:

Focus: Avoiding harm and minimising risk to the patient

Example: Withholding chemotherapy if the side effects outweigh the benefits for a specific patient.

As you can see, these two ethical pillars are often in tension, especially in complex or high-risk medical decisions. In your interview, you’ll be expected to consider how they interact together.

Why Non-Maleficence Matters in Modern Medicine (NHS & GMC Perspective)

In the NHS today, the ethical concept of ‘doing no harm’ is vital. The Pillar of Non-Maleficence underpins patient-centred care, playing an integral role in modern medical decision-making.

Here are some of the key reasons why Non-Maleficence is essential to modern healthcare:

Prevents Over-Treatment and Over-Investigation

Avoiding unnecessary tests or procedures reduces complications and healthcare costs, protecting patient wellbeing by focusing only on interventions that provide real benefit.

Protects the Most Vulnerable

Frail, elderly, or immunocompromised patients may be more harmed than helped by aggressive treatments.
Ensures care is proportionate and personalised to individual needs.

Supports Informed Consent and Shared Decision-Making

Patients must be clearly informed of potential risks and benefits.
Encourages open, honest discussions so patients can make autonomous, informed choices, a core NHS value.

Forms the Basis of GMC Good Medical Practice

GMC guidance states: “Make the care of your patient your first concern.”
This directly reflects the principle of Non-Maleficence, highlighting its legal and professional importance.

Why is non-maleficence important in medicine?

Non-maleficence is essential because it protects patients from avoidable harm and keeps healthcare safe, evidence-based, and ethical. It ensures treatments are proportionate, prevents over-treatment, and encourages doctors to consider the long-term impact of their decisions. It is central to NHS patient safety standards and GMC Good Medical Practice.

Can non-maleficence conflict with autonomy?

Yes - non-maleficence can conflict with autonomy when a patient’s choice may put them at significant risk of harm. In these cases, doctors must balance respecting the patient’s wishes with their duty to protect them. If a patient has capacity, autonomy usually prevails, but if they lack capacity or the risk is severe, non-maleficence may take priority.

The GMC’s Good Medical Practice is built on this principle. The guidance explicitly states: “Make the care of your patient your first concern.” This directly aligns with the Pillar of Non‑Maleficence and reinforces its legal and professional importance.

👉🏻 Read more: NHS Core Values

Why Non-Maleficence Is Important for Your Medical School Interview

Understanding Non-Maleficence is essential - not only to excel in your Medical School Interview, but also to develop the ethical mindset of a doctor in preparation for the future.

Here are some of the reasons why this ethical pillar should be at the centre of your preparation:

Demonstrates ethical maturity in complex interview scenarios

Shows that you can balance clinical judgement with compassion (e.g. when a patient refuses a potentially life-saving treatment)

Knowing when not to act is a skill

Sometimes, doing less as a doctor is safer than doing more. Understanding when intervention could cause harm is a sign of advanced clinical reasoning!

Non-Maleficence links directly to NHS Values

Non-Maleficence aligns with Respect, Compassion and Patient Safety - values which all doctors must uphold.

Helps you to navigate ethical conflicts in interview questions

Scenarios often test your ability to balance Autonomy with Non-Maleficence (patient safety). Understanding how these pillars interact will enhance your interview answers.

Sets the foundation for real-world decision-making

Remember that you are learning about the various Pillars of Medical Ethics to benefit patients by making decisions that protect life and patient dignity, as well as succeed in your medical interviews.

Real-Life Examples of Non-Maleficence in Medicine (Case Studies)

Understanding how the Pillar of Non-Maleficence applies to real medical cases is key to demonstrating ethical understanding during your medical school interview. These examples highlight how doctors must always weigh risk vs benefit, and avoid causing harm to their patients.

Case 1: Charlie Gard - End-of-Life Care and Ethical Conflict

The case of Charlie Gard, a terminally ill baby with mitochondrial DNA depletion syndrome, raised vital questions around non-maleficence, autonomy, and best interest.

Doctors believed further treatment would prolong suffering for Charlie Gard, without a realistic chance of recovery.
Charlie Gard’s parents wanted to pursue experimental treatment abroad, hoping for improvement.
The UK courts ruled that continuing treatment would cause more harm than benefit - demonstrating how non-maleficence can override parental autonomy.

Why It Matters

This case shows that doing no harm can sometimes mean withholding treatment. It challenges future doctors to reflect on compassionate care, end-of-life ethics, and what actions are truly in the patient’s best interest.

👉🏻 Interested in the Charlie Gard Case? Click Here to Read More

Case 2: Overprescription of Antibiotics - Preventing Harm on a Larger Scale

Prescribing antibiotics for viral infections can seem harmless - but in actuality, poses serious risks:

Increases AMR (Antimicrobial Resistance), making future infections harder to treat.
Undermines public health and safety, violating the ethical principle of non-maleficence.

Why It Matters:

This example shows how non-maleficence extends beyond individual patient care - doctors must consider the wider impact of their decisions on public health, aligning with GMC principles and NHS safety guidelines.

👉🏻 Read more: Antibiotic Resistance and Antimicrobial Resistance

MMI Example Question About Non-Maleficence (With Model Answer)

Question:

A parent insists their child should receive an alternative therapy that is unproven and potentially harmful. What do you do?

Answer:

This is an emotional and ethically complex situation. It involves a child who is vulnerable, balanced with their parents wishes and my duty as a doctor to ‘do no harm’ - the Pillar of Non-Maleficence.

My first step would be to speak with the child' s parents openly and compassionately to understand why they are requesting this alternative therapy. I think empathy is essential here - they are likely distressed about the health of their child and trying to do what is best for them. I know that understanding their motives for a potentially risky treatment puts me and the rest of the medical team in a better position to discuss and weigh up the risks and benefits with the parents.

This case involves multiple ethical considerations, and I would carefully weigh each of them. Firstly, I would consider the Pillar of Non-Maleficence. As a doctor, I must prioritise the child’s safety, and their quality of life. Administering a potentially harmful treatment would be causing harm, and violating this ethical principle.

Parental autonomy is also essential to consider in this situation, as it may not remain absolute. Along with the MDT, I would intervene with a parents’ decision if their child is at risk, which in this case, is likely true. Acting in the child’s best interest would be my priority, and offering other, less risky treatment options would be a consideration going forward. Along with my senior colleagues, if the treatment is deemed too aggressive or risky, palliative care could offer the patient more dignity, comfort and peace. This is a situation where not taking steps forward could be the best option for the patient.

Escalating the situation to my senior colleagues and involving the MDT would be my priority in this case. This would include an ethics committee if needed and potentially palliative care specialists. I would want to ensure that decisions are made accounting for the parents’ emotions, balanced with clinical factors.

Overall, I know that the child is my patient, and their safety and best interests must guide all of the decisions that I take. If the alternative treatment poses more of a risk than benefit, I would, along with my colleagues, not support this plan. Instead, my goals would be to support the parents coming to terms with this decision, explore safer and more compassionate ways to manage the illness, and ensure that patient safety is upheld (according to the Pillar of Non-Maleficence).

How to Answer Non-Maleficence Questions in MMI & Panel Interviews

When answering questions about any of the Four Pillars of Medical Ethics, try to follow a guided structure. Below is a structured, high-scoring way to perform well in your MMI:

Define Non-Maleficence - To Do No Harm
Acknowledge the ethical tension in the scenario - What are the Ethical Values in conflict?
Apply each of the Four Pillars of Medical Ethics - How do they interact? Can one override another?
Consider Patient Capacity and Informed Consent
Communicate empathetically, considering views of the patient and their family
Escalate the situation, involving senior colleagues if necessary - In these situations, you are never alone!
Conclude - Your decision must be fair, carefully considered and above all, patient-centred

👉🏻 Read more: MMI Medicine Interview Tips Guide

👉🏻 Read more: Answering Medical Ethics Questions

Practice MMI Questions on Non-Maleficence

A patient insists on being discharged despite a serious risk of stroke. What do you do?
Parents demand a homeopathic treatment for their child who has a bacterial infection, despite the child requiring a course of antibiotics in the hospital. How do you respond?

👉🏻 Read more: 280 MMI Medical School Practice Interview Questions

FAQs - The Pillar of Non-Maleficence

1. What does non-maleficence mean in medical ethics?

Non-maleficence means “do no harm.” It is a doctor’s duty to avoid causing physical, psychological, or emotional harm to patients, whether through action, negligence, or poor decision-making.

2. How is non-maleficence different from beneficence?

Non-maleficence focuses on avoiding harm, while beneficence focuses on doing good. Doctors must balance both — for example, a treatment may help (beneficence) but cause serious side effects (non-maleficence).

3. Why is non-maleficence important in medicine?

It protects patients from unnecessary harm, ensures treatments are safe and evidence-based, and underpins NHS patient safety standards. It also guides doctors to avoid overtreatment, unnecessary tests, and risky interventions.

4. Can non-maleficence override patient autonomy?

Yes, in specific situations. If a patient lacks capacity or if a decision poses serious risk, doctors may act in the patient’s best interests. If the patient has capacity and understands the risks, autonomy usually prevails.

5. What is an example of non-maleficence in modern healthcare?

A common example is not prescribing antibiotics for viral infections. This avoids side effects and protects against antimicrobial resistance (AMR), preventing wider public harm.

6. How does non-maleficence relate to informed consent?

Doctors must explain all material risks of a treatment so the patient can make a safe, informed choice. This protects patients from unintended harm and ensures ethical, transparent care.

7. What real-life NHS cases involve non-maleficence?

Cases like Charlie Gard demonstrate how non-maleficence can guide decisions to stop treatments that may prolong suffering. It highlights the need to act compassionately and prevent harm at end of life.

8. Does non-maleficence ever mean “doing nothing”?

Yes. Sometimes withholding or withdrawing treatment is safer and more ethical than intervening - for example, choosing palliative care instead of aggressive treatment with no meaningful benefit.

9. How might non-maleficence be tested in an MMI interview?

MMI stations often test whether you can balance non-maleficence with autonomy, communicate risks clearly, escalate to seniors appropriately, and prioritise patient safety in complex ethical scenarios.

10. How do doctors apply non-maleficence day-to-day?

Clinicians use it when:

Weighing risks vs benefits
Avoiding unnecessary tests
Preventing medical errors
Choosing safer alternatives
Protecting vulnerable patients

It guides safe, ethical practice across all specialties.

Check out our Medicine Interview Tutoring and Interview Question Bank which has over 400 medicine questions and answer guides for your practice.